APM vs GPT Partionining Issue???

[jimmymac_4]

I'm a retired IT professional with 35+ years of experience. Although I am Windows proficient, I am new to the MAC. I have a new Intel/Leopard based iMac. It is my understanding that the proper hard disk formatting for this particular computer is GPT (GUID Partition Table) as opposed to APM (Apple PartitionMap). I have a double backup scheme in place with two separate external firewire drives. System Profiler indicates that my Time Machine hard disk has GPT (GUID) partitioning, but my Super Duper Hard disk has APM partitioning. I would have expected that a clone of my internal (boot) drive would have produced a GPT (GUID) clone/copy. I thought that I initially partitioned my Super Duper backup drive as GPT (GUID), so I am baffled by what I have just discovered.

1. Why would my Super Duper clone (backup) have APM partitioning?
2. Is this any cause for concern?
3. Since I already have Time Machine in place and my iMac appears to be stable, should I just repartition (zero) my Super Duper drive and start from scratch?

Thanks in advance.